Endoscopes are commonly used to view within an actual or potential space inside a subject (e.g., a human, or animal) or manufactured structure (e.g., an engine or a pipe) while performing a therapeutic or diagnostic procedure. Typically, an endoscope has a control handle coupled to an elongated portion (e.g., a flexible elongated portion, a rigid elongated portion, a semi-rigid elongated portion). During use of the endoscope, the control handle remains outside the subject while the elongated portion is at least partially disposed inside the subject. Generally, the elongated portion has one or more optical components (e.g., one or more lenses, fiber optics, video imager) to illuminate and view the region inside the subject, and the control handle has one or more devices designed to control the optical components (e.g., to control light intensity, focus an image, display and image, digitize an image) and the position of the elongated portion in the subject.
Typically the light source, the light source power supply and other features and controls (such as irrigation and suction) are placed in a separate console that is connected to the endoscope handle by an umbilical cable that includes a light guide. Traditional light sources for endoscopic use are generally of two types: incandescent filament lamps and arc lamps. Both types of lamps are very inefficient in converting electrical power to light, and consequently produce large amounts of heat that must be dissipated. Because of the heat generated and the need for a bulky light source power supply, these light sources typically reside outside of the endoscope itself.
An illustrative endoscope according to the prior art is shown in FIG. 1, which is simplified from FIG. 1 of U.S. Pat. No. 5,630,783. The endoscope 20 includes a housing or handle 22 having an elongated distal portion 24 that supports a flexible tube 26. The handle 22 also includes an eyepiece 28 at the proximal end of the handle 22. The eyepiece 28 can include a focus ring 30. The tube 26 typically includes an outer covering 32 constructed from a low-friction polymer. The distal end 34 of the tube 26 typically includes a polished metal end cap 35 having a plurality of exit ports. The handle 22 includes a movable steering control 36 with a steering lever or knob 38. The steering lever 38 moves (arrow 40) proximally and distally along the handle to control a pair of steering cables (not shown) within the tube 26. The steering cables enable the distal end 34 of the tube 26 to bend. The steering control 36 is mounted on an enlarged ball 42 located between the proximal end and the distal end of the handle 22.
A connector 50 links the ball 42 with a fiber optic light source cable 44 that communicates with a light source 46 according to the prior art. The light source 46 is, typically, a variable-intensity incandescent or arc lamp that draws power from a conventional AC power source via an electrical cord 48. An associated internal illumination light guide (not shown) is optically linked within the ball 42 of the handle 22 with the light source cable 44. The internal illumination light guide extends through the distal end 24 of the handle 22 and passes along the full length of the tube 26, and is exposed at the distal end 34 of the tube 26 to provide light at the distal end. According to the prior art, an irrigation/instrument assembly 52 or other fitting is optionally provided at the distal end 24 of the handle 22. The assembly 52 interconnects with an internal tube (not shown) that exits at the distal end 34 of the tube 26. The assembly 52 includes an instrument port 53 that provides a conduit for guiding an actuating mechanism of an instrument such as the grasper 55 located at the tube's distal end 34. A remote plunger assembly 54 with a movable finger control 59 controls the grasper 55. The irrigation/instrument assembly 52 also includes a fluid inlet 57 that can comprise a Luer-style fitting connected with a sterile tubing 56 that can terminate in a source of sterile saline or water used as an irrigation fluid. Both instruments and irrigation fluid can pass down a single internal tubing (not shown) to exit at the distal end 34.
Prior attempts to produce endoscopes that are not tethered by such a fiber optic light source cable 44 to an external light source 46 have produced light sources and battery power supplies that are external to and separate from the endoscope handle, yet still use inefficient light sources, such as halogen lamps. An example of this form of prior art endoscope is illustrated by FIG. 2, which is also simplified from FIG. 2 of U.S. Pat. No. 5,630,783. This prior art endoscope 120 includes a body or housing 122 having a distal end 124 and a proximal eyepiece 128. The eyepiece 128 includes an adjustment or focus ring 130. The distal end 124 of the housing 122 supports a semi-rigid, flexible, tube 126, which is covered with a flexible, low friction, sheathing 132, and includes a distal end 134 having a polished metallic ring 135 with a series of openings. A steering control 136 including a movable steering control lever 138 is mounted on an enlarged ball section 142 of the housing 122. A fitting 280 is provided adjacent the distal portion 124 of the housing 122 for the introduction of instruments, such as graspers and biopsy forceps, medicaments and small quantities of saline or water irrigation fluids.
This prior art endoscope has a self-contained illumination source 180 attached in the position of the fiber optic light source cable connector 50 of FIG. 1. The source 180 utilizes a high intensity incandescent light bulb. The bulb can be a halogen-type bulb for greater intensity and whiter light. The battery and switch 204 are self-contained within a removable housing 208 that is joined to the upper portion of the handle 122 by a threaded ring coupling 210. The battery can be a rechargeable nickel-cadmium or equivalent battery, such as a lithium-ion battery. Other endoscopes with an add-on battery powered light sources using an incandescent halogen bulb are known, for example, at http://www.pentaxmedical.com/Products/Bronchoscopy/PortableBronch.asp.
Such add-on battery powered light sources not only are inefficient and clumsy, but the connection to the endoscope handle is an additional site for leakage, corrosion and contamination. In general, after each use in a medical procedure, the endoscope is cleaned to remove detritus, and subsequently disinfected and/or sterilized. Standard cleaning and disinfection procedures require that the entire endoscope, including the endoscope handle, is completely immersible and watertight, and leak testing is performed routinely as part of the cleaning and disinfection process. Fluids used during the disinfection process (http://www.fda.gov/cdrh/ode/germlab.html), such as activated alkaline glutaraldehyde, peracetic acid and orthophthaldehyde, are harsh and corrosive chemicals. Fluid leakage into the interior of the endoscope handle and contact with electronic circuits and components can damage both a light source and its power supply if located within the endoscope handle.
Thus, there is a need for a fully self-contained endoscope that is not tethered to an external light and/or power source and that can withstand multiple uses and cleanings while maintaining the integrity of the liquid sensitive components of the endoscope.